Results from 4 years monitoring of pharmaceuticals in hospital effluents and in the receiving WWTP plant - occurrence and environmental risk

The results of pharmaceuticals in wastewater effluents from a Norwegian hospital as well in the influent and effluents of the receiving urban wastewater treatment plant (WWTPs) presented here are the first major published study in Norway (Thomas mfl. 2007) since 2007. A larger number (n=157) of pharmaceuticals was investigated in this study than previously. We found that the concentrations of the pharmaceuticals in hospital effluents that were included also in the previous study, were mostly higher compared to in 2007, though the hospitals were not the same. We also compared the concentrations of pharmaceuticals hospital effluents, and WWTP influent and effluent with predicted environmental concentrations (PECs) based on sales of pharmaceuticals. As expected, the concentrations in hospital effluents were on average higher than PECs. The concentrations in WWTP influent was also on average somewhat higher than PEC, but WWTP effluents were on average lower than PECs. For the WWTP influent, the concentrations were not significantly different than estimates of PECs. A simple risk assessment of the WWTP effluents indicated that the environmental risk of the female sex hormones estrone and estradiol were highest. The risk quotients (RQ) of the anti-inflammatory drug diclofenac and the antibiotics ciprofloxacin, azitromycin and sulfametoksazol were higher than 1, indicating that environmental effects cannot be excluded. The lack of toxicity studies of several pharmaceuticals makes an environmental risk assessment impossible. Therefore, the environmental risk for most (62%) of the pharmaceuticals, remains unknown.